Features Of Dystrophy Research Articles

G.P.9: Adult onset distal and proximal myopathy with complete ophthalmoplegia and bulbar involvement due to de novo mutation in MYH2

Oculopharyngodistal (OPD) myopathy (OMIM 164310) is a clinically and genetically distinct entity for which a molecular defect has not yet been found. Mutations in MYH2 have been described in patients with ophthalmoplegia presenting with multiple contractures at birth, later developing a proximal myopathy in the adulthood. We present a patient clinically classified as OPD myopathy who was found to carry a MYH2 de novo mutation. An Australian male of Italian background presented at 18 years old with predominantly distal but also proximal limb weakness, ophthalmoplegia, dysphagia and facial weakness. He later developed respiratory involvement. Parents were not affected. The course of the disease was progressive, being wheelchair bound by the age of 50. He had 4 muscle biopsies done from age 20 to 46, none of which showed rimmed vacuoles. Dystrophic features, type I predominance, and abundant lobulated fibres were consistently found. Ultrastructure showed foci of Z band streaming. In one biopsy, total absence of type II fibres was seen. However, unlike previously reported cases, the structural changes did not seem to be more severe at an older age. A panel of 277 neuromuscular disease-causing genes were sequenced using next generation sequencing methods. A missense variation in exon 39 of MYH2: c.T5630C (p.L1877P) not previously seen in normal populations, was found. The mutation introduces a proline in the tail of myosin, presumably interfering with the assembly of thick filaments, as in MYH7 mutations causing Laing distal myopathy. Segregation studies proved it to be a de novo mutation. This case expands the phenotype of mutations in MYH2 to include predominantly distal limb weakness. We suggest that mutations in MYH2 should be considered in patients with distal weakness and ophthalmoplegia.

L.I.2: The ABC of autosomal recessive limb girdle muscular dystrophy

Autosomal recessive limb girdle muscular dystrophy (LGMD2) is a group of heterogeneous muscle diseases that share several common denominators. Beside the same mode of inheritance, patients develop progressive weakness and wasting of their shoulder and pelvic girdle muscles whilst muscle biopsies generally show dystrophic histological features. Coming to a specific diagnosis in a patient with LGMD2 can be quite challenging. Diagnostic clues for the clinician can be the age of onset, the ethnic background, the involvement of respiratory muscles, the heart or other organ systems, the selective pattern of muscle pathology and immunoanalysis of the muscle biopsy. Next generation sequencing strategies, especially gene panel and exome sequencing approaches, are gradually replacing the often cumbersome gene by gene mutation analysis and should help to provide all patients with LGMD2 with a precise diagnosis over the next few years. The identification of the underlying genetic defect in almost 20 different forms of LGMD2 so far has helped to generate animal models and to study disease pathogenesis. Nevertheless there is currently no licensed drug for LGMD2 and treatment strategies focus on the improvement of symptoms. One of the biggest challenges is the low number of identified LGMD2 patients. Whereas in some forms of LGMD2 several hundred patients have been diagnosed, in other forms only very few families have been characterized. Over the coming years it will be important to develop a successful translational research pathway in LGMD2 by creating patient registries, developing standards of care and establishing validated outcome measures and disease biomarkers. These objectives can only be achieved through a close partnership between scientists, healthcare professionals, patient organizations, the pharmaceutical industry and regulators. The presentation will focus on the current stage of translational research approaches in LGMD2 and on future perspectives.

G.P.225: Concomitant alpha and gamma sarcoglycan deficiencies in a Turkish boy with a novel deletion in the alpha sarcoglycan gene

Limb-girdle muscular dystrophy type 2D (LGMD-2D) is caused by autosomal recessive defects in the alpha-sarcoglycan gene located on chromosome 17q21. In this study, we present a child with alpha-sarcoglycanopathy and describe a novel deletion in the alpha-sarcoglycan gene. A 5-year-old boy had a very high serum creatinine phosphokinase level, which was determined incidentally, and a negative molecular test for the dystrophin gene. Muscle biopsy showed dystrophic features. Immunohistochemistry showed that, there was diminished expression of alpha and gamma sarcoglycans. DNA analysis revealed a novel 7bp homozygous deletion in exon 3 of the alpha-sarcoglycan gene. His parents were consanguineous heterozygous carriers of the same deletion. We believe this is the first confirmed case of primary alpha-sarcoglycanopathy with a novel deletion in Turkey. In addition, this study demonstrated that, both muscle biopsy and DNA analysis remain important methods for the differential diagnosis of muscular dystrophies because dystrophinopathies and sarcoglycanopathies are so similar.

G.P.182: Severe and progressive mitochondrial myopathy in early childhood: novel mutations in TK2 gene

The Thymidine kinase 2 (TK2) gene encodes an enzyme of mitochondrial expression involved in the deoxyribonucleotide triphosphates metabolism necessary for replication of mtDNA. Mutations in TK2 are associated with mtDNA depletion syndrome with a well-characterized phenotype, consisting of a severe and progressive generalised muscular weakness and respiratory failure during the first years of life. The aim of this study is to describe the clinical phenotype of 3 Spanish patients and the finding of a novel mutation in TK2 gene. We present 3 unrelated male patients from non-consanguineous families, with normal early development until they showed a progressive hypotonia and muscular weakness with a fast motor regression between 14–24 months of age. Two patients (currently 2 and 3 years of age) lost the gait few months after starting the first clinical symptoms and the other at the age of 7, this patient died at 8,5 years. At present, the other 2 patients are about to start treatment with deoxypyrimidine mono phosphates. All patients presented a mild increase of serum CK and lactate levels. Electromyogram showed a myopathic pattern. Muscle biopsy showed dystrophic features and COX negative fibres. Lipid vacuoles and ragged red fibres (RRF) were observed. The activity of respiratory chain complexes I, III and IV was decreased but there was a normal activity in complex II. Genetic studies showed more than 80 % of depletion in mtDNA in muscle. Sequence analysis of the TK2 gene found two heterozygous pathogenic mutations previously described in 2/3 patients. A novel mutation (c.623A > G; p. Tyr208Cys and c.388C > T p. Arg130Trp) was found in one patient with a significant reduction of TK2 activity studied in fibroblast. Severe and rapidly progressive muscle weakness in early childhood should prompt clinicians to search for evidence of mitochondria dysfunction and alert about a possible diagnosis of TK2 deficiency.

G.P.184: Mitochondrial DNA depletion in single fibers in a patient with novel TK2 mutations

The mitochondrial DNA (mtDNA) depletion syndrome is a genetically heterogeneous group of diseases caused by nuclear gene mutations and secondary reduction in mtDNA copy number. We describe a patient with progressive muscle weakness and increased creatine kinase and lactate levels. Muscle weakness was first noted at age 1.5years and he died of respiratory failure and bronchopneumonia at age 3.5years. The muscle biopsy showed dystrophic features with ragged red fibers and numerous cytochrome c oxidase (COX)-negative fibers. qPCR analysis demonstrated depletion of mtDNA and sequence analysis of the mitochondrial thymidine kinase 2 (<i>TK2</i>) gene revealed two novel heterozygous variants, c.332C>T, p. (T111I) and c.156+5G>C. Quantitative analysis of mtDNA in single muscle fibers demonstrated that COX-deficient fibers showed more pronounced depletion of mtDNA when compared with fibers with residual COX activity (P <0.01, n=25). There was no evidence of manifestations from other organs than skeletal muscle although there was an apparent reduction of mtDNA copy number also in liver. The patient showed a pronounced, albeit transient, improvement in muscle strength after onset of treatment with coenzyme Q10, asparaginase, and increased energy intake, suggesting that nutritional modulation may be a therapeutic option in myopathic mtDNA depletion syndrome.

G.P.226: Sarcolemmal deficiency of sarcoglycan complex in an eighteen months old Turkish boy with a huge deletion in the beta sarcoglycan gene

Limb-girdle muscular dystrophy type 2E (LGMD-2E) is caused by autosomal recessive defects in the beta-sarcoglycan gene located on chromosome 4q12. In this study, the clinical findings, histopathological features and molecular genetic data in a boy with beta-sarcoglycanopathy are presented. An eighteen-month-old boy had a very high serum creatinine phosphokinase level, which was determined incidentally. He had consanguineous parents. The result of molecular analyses for dystrophin gene was found normal. He underwent a muscle biopsy which showed dystrophic features. Immunohistochemistry showed that, there was a total loss of sarcolemmal sarcoglycan complex (alpha, beta, delta and gamma sarcoglycans) while sarcolemmal dystrophin expression was normal. DNA analysis revealed a huge deletion in the beta-sarcoglycan gene. The deletion was homozygous and occurred from exon 1 to 6. This study demonstrated that the total absence or abnormal expressions of all 4 sarcoglycans are more likely to indicate a primary defect in the beta sarcoglycan gene.

G.P.278: Facial dysmorphism in FKRP limb-girdle muscular dystrophy: About two cases

Mutations in the Fukutin-Related Protein gene (FKRP) account for a broad spectrum of phenotypes ranging from severe congenital muscular dystrophies to much milder limb-girdle muscular dystrophy (LGMD2I). In both, weakness and wasting of shoulder-girdle muscles, primary restrictive respiratory and cardiac involvement are classical features. To our knowledge, facial dysmorphic features have not been reported yet. The first woman developed, at age 12, a progressive pelvic weakness. Two biopsies were performed showing a dystrophic pattern with normal classical immunohistochemistry. At age 38, she was confined in a wheelchair and suffered from respiratory insufficiency. She also had a mild cardiomyopathy. As she presented macroglossia, analysis of the FKRP gene was performed and two compound mutations p.Leu276Ile and p.Glu343X were found. The second woman was born of a consanguineous union. From childhood, she had difficulties running and rising from the floor. At 12, she developed a limb-girdle weakness that confined her in a wheelchair at age 26. Vital capacity was normal, as well as US heart exam. Muscular biopsy showed classical dystrophic features with normal immunohistochemistry and Western blot. She had no macroglossia but her face looked alike our first FKRP patient. Indeed, both women presented hypertelorism, large palpebral fissures, depressed nasal bridge, prognathism and thick lips being responsible for a dramatic physical resemblance although they were unrelated. FKRP gene analysis was therefore performed and a homozygous mutation p.Leu276Ile was found. Limb-Girdle weakness associated with macroglossia and calf hypertrophy are classical clues for FKRP gene sequencing. Some mutations have more frequent macroglossia or calf hypertrophy than others. But facial dysmorphia has not been reported in this disease so far. This dysmorphia represent a real diagnosis help in our second patient and should be searched each time a LGMD patient is considered. Mutations in the Fukutin-Related Protein gene (FKRP) account for a broad spectrum of phenotypes ranging from severe congenital muscular dystrophies to much milder limb-girdle muscular dystrophy (LGMD2I). In both, weakness and wasting of shoulder-girdle muscles, primary restrictive respiratory and cardiac involvement are classical features. To our knowledge, facial dysmorphic features have not been reported yet. The first woman developed, at age 12, a progressive pelvic weakness. Two biopsies were performed showing a dystrophic pattern with normal classical immunohistochemistry. At age 38, she was confined in a wheelchair and suffered from respiratory insufficiency. She also had a mild cardiomyopathy. As she presented macroglossia, analysis of the FKRP gene was performed and two compound mutations p.Leu276Ile and p.Glu343X were found. The second woman was born of a consanguineous union. From childhood, she had difficulties running and rising from the floor. At 12, she developed a limb-girdle weakness that confined her in a wheelchair at age 26. Vital capacity was normal, as well as US heart exam. Muscular biopsy showed classical dystrophic features with normal immunohistochemistry and Western blot. She had no macroglossia but her face looked alike our first FKRP patient. Indeed, both women presented hypertelorism, large palpebral fissures, depressed nasal bridge, prognathism and thick lips being responsible for a dramatic physical resemblance although they were unrelated. FKRP gene analysis was therefore performed and a homozygous mutation p.Leu276Ile was found. Limb-Girdle weakness associated with macroglossia and calf hypertrophy are classical clues for FKRP gene sequencing. Some mutations have more frequent macroglossia or calf hypertrophy than others. But facial dysmorphia has not been reported in this disease so far. This dysmorphia represent a real diagnosis help in our second patient and should be searched each time a LGMD patient is considered.

Mitochondrial myopathy with dystrophic features due to a novel mutation in the MTTM gene

A 61-year-old woman with a 5-year history of progressive muscle weakness and atrophy had a muscle biopsy characterized by a combination of dystrophic features (necrotic fibers and endomysial fibrosis) and mitochondrial alterations [ragged-red, cytochrome c oxidase (COX)-negative fibers]. Sequencing of the whole mtDNA, assessment of the mutation load in muscle and accessible nonmuscle tissues, and single fiber polymerase chain reaction. Muscle mitochondrial DNA (mtDNA) sequencing revealed a novel heteroplasmic mutation (m.4403G>A) in the gene (MTTM) that encodes tRNA(Met). The mutation was not present in accessible nonmuscle tissues from the patient or 2 asymptomatic sisters. The clinical features and muscle morphology in this patient are very similar to those described in a previous patient with a different mutation, also in MTTM, which suggests that mutations in this gene confer a distinctive "dystrophic" quality. This may be a diagnostic clue in patients with isolated mitochondrial myopathy.

Mitochondrial DNA depletion in single fibers in a patient with novel TK2 mutations

The mitochondrial DNA (mtDNA) depletion syndrome is a genetically heterogeneous group of diseases caused by nuclear gene mutations and secondary reduction in mtDNA copy number. We describe a patient with progressive muscle weakness and increased creatine kinase and lactate levels. Muscle weakness was first noted at age 1.5years and he died of respiratory failure and bronchopneumonia at age 3.5years. The muscle biopsy showed dystrophic features with ragged red fibers and numerous cytochrome c oxidase (COX)-negative fibers. qPCR analysis demonstrated depletion of mtDNA and sequence analysis of the mitochondrial thymidine kinase 2 (TK2) gene revealed two novel heterozygous variants, c.332C>T, p.(T111I) and c.156+5G>C. Quantitative analysis of mtDNA in single muscle fibers demonstrated that COX-deficient fibers showed more pronounced depletion of mtDNA when compared with fibers with residual COX activity (P<0.01, n=25). There was no evidence of manifestations from other organs than skeletal muscle although there was an apparent reduction of mtDNA copy number also in liver. The patient showed a pronounced, albeit transient, improvement in muscle strength after onset of treatment with coenzyme Q10, asparaginase, and increased energy intake, suggesting that nutritional modulation may be a therapeutic option in myopathic mtDNA depletion syndrome.

Whiplash: Same Elephant, Different Room

Musculoskeletal injury can cause acute pain and can also trigger chronic pain. The mechanisms resulting in these 2 outcomes are essentially different, with acute pain relating primarily to peripheral nociception and chronic pain relating primarily to central sensitization. Acute musculoskeletal pain usually resolves with time or treatment. Chronic pain, by definition, persists and associates with significant longterm health effects and diminished quality of life (QOL). Despite the importance of this problem, the issues surrounding persisting pain after injury remain controversial1. Aspects of postinjury pain and disability are addressed in this issue of The Journal through followup of persons involved in minor trauma from motor vehicle accidents2. The clinical features of patients with persisting pain after trauma, where the inciting lesion has resolved, are usually distinctive and embody a number of characteristic pain phenotypes. Central sensitization is the most prominent contributing mechanism3. Common examples are fibromyalgia (FM), regional pain syndrome, and complex regional pain syndrome (CRPS)4. These disorders are characterized by widespread or regionalized pain in a distribution that cannot be explained by an abnormality of a specific localized musculoskeletal or neural structure, be it in the periphery or in the spinal area. The pain may be segmental and often accompanied by unpleasant non-neuroanatomical sensory sensations within the same region. There is widespread or regional lowering of pain threshold elicited clinically by the determination of abnormal tenderness on palpation, more prominent in selected areas known as tender points. Muscular tightness, co-contraction, and development of trigger points are common. There is often mild soft tissue swelling and dermatographia, indicative of neurogenic inflammation. In CRPS more prominent vasomotor, sudomotor, muscle, and dystrophic features are present5. In addition to these physical signs, patients complain to a varying degree about sleep disturbance, fatigue, cognitive dysfunction, … Address correspondence to Dr. Littlejohn, Suite H, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria, Australia; E-mail: Geoff.littlejohn{at}monash.edu

A 19-year-old ambulant Duchenne patient with stunted growth on long-term corticosteroids

This young man with Duchenne muscular dystrophy (DMD) received corticosteroids from 2.4 years of age [1]. Needle muscle biopsy of the quadriceps taken at the age of 40 days showed dystrophic features and complete absence of dystrophin by immunofluorescence (Dys 1–3) and Western blot [1]. He had a deletion of exon 20–25 (out-of-frame) in the dystrophin gene [1]. The corticosteroid regimen was daily prednisone 0.75 mg/kg for the first 2 weeks, then on alternate days (1.25 mg/kg every other day). At the age of 5.5 years, to possibly lower the risk of weight gain, he was moved to deflazacort 1.5 mg/kg every other day. After the age of 13 years, if he had more weakness or fatigue, deflazacort was increased by 0.90 mg/kg daily for 1–3 months. At the last follow-up, he was on deflazacort 36 mg daily. He lost the ability to rise from the floor at age 17. At the age of 18, he started using a wheel chair to cover long distances. At the age of 19, he was able to walk 10 m in 15 s and to climb a few stairs slowly with aid of railings. His height (Fig. 1) was 144.7 cm, weight was 41.5 kg, and body mass index (BMI) was 19.8. He had a decline in growth rate, starting just after the first year of corticosteroid treatment. His height was between 50 and 75th percentiles at the age of 2 years, below 2 standard deviations (SDs) at 6 years, below 3 SD at 13 years, 3.98 SD at 16 years, and 4.1 SD at 19 years. He had delayed puberty and received androgen treatment between

Concomitant alpha- and gamma-sarcoglycan deficiencies in a Turkish boy with a novel deletion in the alpha-sarcoglycan gene.

Limb-girdle muscular dystrophy type 2D (LGMD-2D) is caused by autosomal recessive defects in the alpha-sarcoglycan gene located on chromosome 17q21. In this study, we present a child with alpha-sarcoglycanopathy and describe a novel deletion in the alpha-sarcoglycan gene. A 5-year-old boy had a very high serum creatinine phosphokinase level, which was determined incidentally, and a negative molecular test for the dystrophin gene. Muscle biopsy showed dystrophic features. Immunohistochemistry showed that there was diminished expression of alpha- and gamma-sarcoglycans. DNA analysis revealed a novel 7 bp homozygous deletion in exon 3 of the alpha-sarcoglycan gene. His parents were consanguineous heterozygous carriers of the same deletion. We believe this is the first confirmed case of primary alpha-sarcoglycanopathy with a novel deletion in Turkey. In addition, this study demonstrated that both muscle biopsy and DNA analysis remain important methods for the differential diagnosis of muscular dystrophies because dystrophinopathies and sarcoglycanopathies are so similar.

Transgenic mice expressing mutant Pinin exhibit muscular dystrophy, nebulin deficiency and elevated expression of slow-type muscle fiber genes

Pinin (Pnn) is a nuclear speckle-associated SR-like protein. The N-terminal region of the Pnn protein sequence is highly conserved from mammals to insects, but the C-terminal RS domain-containing region is absent in lower species. The N-terminal coiled-coil domain (CCD) is, therefore, of interest not only from a functional point of view, but also from an evolutionarily standpoint. To explore the biological role of the Pnn CCD in a physiological context, we generated transgenic mice overexpressing Pnn mutant in skeletal muscle. We found that overexpression of the CCD reduces endogenous Pnn expression in cultured cell lines as well as in transgenic skeletal muscle fibers. Pnn mutant mice exhibited reduced body mass and impaired muscle function during development. Mutant skeletal muscles show dystrophic histological features with muscle fibers heavily loaded with centrally located myonuclei. Expression profiling and pathway analysis identified over-representation of genes in gene categories associated with muscle contraction, specifically those related to slow type fiber. In addition nebulin (NEB) expression level is repressed in Pnn mutant skeletal muscle. We conclude that Pnn downregulation in skeletal muscle causes a muscular dystrophic phenotype associated with NEB deficiency and the CCD domain is incapable of replacing full length Pnn in terms of functional capacity.

The Rag2–Il2rb–Dmd– Mouse: a Novel Dystrophic and Immunodeficient Model to Assess Innovating Therapeutic Strategies for Muscular Dystrophies

The development of innovative therapeutic strategies for muscular dystrophies, particularly cell-based approaches, is still a developing field. Although positive results have been obtained in animal models, they have rarely been confirmed in patients and resulted in very limited clinical improvements, suggesting some specificity in humans. These findings emphasized the need for an appropriate animal model (i.e., immunodeficient and dystrophic) to investigate in vivo the behavior of transplanted human myogenic stem cells. We report a new model, the Rag2(-)Il2rb(-)Dmd(-) mouse, which lacks T, B, and NK cells, and also carries a mutant Dmd allele that prevents the production of any dystrophin isoform. The dystrophic features of this new model are comparable with those of the classically used mdx mouse, but with the total absence of any revertant dystrophin positive fiber. We show that Rag2(-)Il2rb(-)Dmd(-) mice allow long-term xenografts of human myogenic cells. Altogether, our findings indicate that the Rag2(-)Il2rb(-)Dmd(-) mouse represents an ideal model to gain further insights into the behavior of human myogenic stem cells in a dystrophic context, and can be used to assess innovative therapeutic strategies for muscular dystrophies.

P.1.11 Development of a registry and a database for a nation-wide Italian collaborative network on congenital muscular dystrophy

Congenital muscular dystrophies (CMD) are rare diseases and small patient number represents the major impediment to progress in research and care. Classically the term CMD includes a group of genetically, clinically and biochemically distinct entities sharing clinical and pathological features such as early presentation of weakness and hypotonia and dystrophic features on muscle biopsy. In the last years the identification of several new genes responsible for different forms of CMD has not only expanded the spectrum of the known forms of CMD (to date over 20 genes responsible for CMD forms have been identified) but has produced exciting progresses in the understanding of the mechanisms underlying this group of disorders. However the real incidence and prevalence of CMD in populations is not sufficiently known. The aim of this Project is to establish the prevalence of CMD in Italy by harmonizing a nation-wide network including all the tertiary care centers. The possibility to join an international database will also provide the opportunity to make the data available for larger international studies and to contribute to a better understanding of the prevalence of CMD in the different countries. Preliminary results show 302 cases of CMD in Italy subdivided into: 47% dystroglycanopathies, 25% laminin alpha2 deficient CMD, 14% collagen VI deficient CMD, 6% mutations in SEPN1, 4% laminopathies, 4% others. All the patients with dystroglycanopathies and CMD phenotype have been screened for the first 6 known genes and they are being screened for the recently recognized new genes. As the study includes all the Italian tertiary care centers for pediatric neuromuscular disorders, we can presume that our findings will provide an estimate of at least all the cases of CMD.

P.9.9 A novel de novo mutation in ACTA1 causes a congenital myopathy with misleading type 1 fiber predominance and a peculiar MRI

Nemaline myopathy is a genetically heterogeneous disease showing wide clinical variability. Disease severity and prognosis range from neonatal death to almost normal motor function. We report on a 19-year-old boy with reportedly absence of fetal movements. He was severely hypotonic at birth with dolichocephaly, weak facial movements, bilateral clubfoot and feeding difficulties, requiring nasogastric tube feeding; gastrostomy was applied at age 3months and removed at 12. Motor milestones were delayed: walking at 24months, with marked foot drop. He has always been unable to eat solid foods because of impaired chewing. Since the age of 8 he is on nocturnal BiPAP. A first muscle biopsy of the quadriceps at age 8months, and a second biopsy of vastus lateralis performed at age 10years, both showed variability in fiber diameter, marked type 1 fiber predominance (90%), with neither evidence of endomysial fibrosis nor nemaline bodies. A third biopsy of the right deltoid muscle at age 19 showed marked fibrosis and dystrophic features with proliferation of nemaline bodies. Current neurological examination showed a young intelligent man with nasal voice, generalized weakness, ptosis, and no limitation of ocular movements. The MRI showed marked involvement of glutei muscles, together with involvement of sartorius, tibialis anterior and peroneus longus. Sequencing of ACTA1 in blood DNA detected a novel heterozygous de novo variant. The new mutation affects a highly preserved Threonine. No mutations were detected in SEPN1 and TPM3. We report on a long follow-up in a patient with a congenital myopathy related to a de novo mutation in ACTA1. Of the 3 muscle biopsies performed, the first 2 were not contributory for diagnosis and the clinical presentation did not offer additional clinical clues. The last muscle biopsy performed in adulthood revealed nemaline rods prompting specific molecular investigations and ultimately allowing a genetic diagnosis.

P.19.6 PIK3CA somatic mutation in congenital monomelic muscular hypertrophy of the upper extremity. Case report

Congenital isolated unilateral hypertrophy of upper extremity secondary to muscular hyperplasia is a rare phenomenon of unknown etiology. There are only few reports variably defining it as an aberrant muscle syndrome or congenital monomelic muscular hypertrophy. We report the case of a 6-year old girl with a congenital enlargement of the whole left arm, and hand deformity. MRI showed a generalized enlargement given by homogenous increase in muscle bulk with no fat replacement together with aberrant muscles in the hand. No dysfunctions of the shoulder, elbow or wrist were detected. The patient presented normal development, with no cutaneous stigma nor additional features usually seen in Proteus syndrome. The left hand was wider with ulnar drift of the index finger, increased muscle bulk of the first dorsal interosseous and widening of the 2nd and 3rd metacarpal space. A muscle biopsy of the prominent tissue in the dorsal face of the hand revealed dystrophic features with abnormally increased variability of fibres together with many hypertrophic fibres associated with increased perimysial and endomysial fibrosis. Type 1 fiber predominance, and disorganization of the intermyofibrilar network was evident at histochemistry for NADH, COX and SDH. Mosaic activating mutation in the PI3K–AKT cell signaling pathway have been described in overgrowth syndromes such as Proteus syndrome, CLOVES syndrome, megalencephaly–capillary malformation, fibroadipose hyperplasia and macrodactyly. Given the relationship of mosaic activating mutations in the PI3K–AKT cell signaling pathway with other overgrowth syndromes, Sanger sequencing for AKT, PIK3CA, and PTEN was performed. A mutation c.3140A > G, p.H1047R in PIK3CA was detected in DNA from the affected muscle but not from blood leucocytes. Isolated congenital upper limb hypertrophy with aberrant hand muscles is another condition related genetically to overgrowth syndromes.

P.1.15 Clinical heterogeneity of myopathy related to partial merosin deficiency

Mutations in the <i>LAMA2</i> gene underlie a severe congenital type of muscular dystrophy (MDC1A). We report the clinical, histological and genotypic features of 2 patients aged respectively 35 and 31years-old, presenting unusual phenotypes. The first patient, aged 36, exhibit a late-onset muscle weakness predominantly in the limb girdle. Contractures of the elbow, wriest, fingers and Achilles tendons were the first symptoms with an onset at 15years of age. Pelvic muscle weakness was observed at 25years of age. The CK was elevated (2000UI/L). In addition, he presented at age 30 a dilated cardiomyopathy with ventricular arrhythmias, requiring the implantation of a cardioverter-defibrillator. The second patient, aged 31years, presented axial weakness at age 1, followed by the occurrence of rigid spine around 10years of age associated to contractures at elbow, fingers, hips and Achilles tendons. At age 30, he had predominantly axial and limb girdle muscle weakness associated with upward gaze deficit. He has also generalized and partial complex seizures, beginning at age 6. The brain MRI disclosed bilateral occipital polymicrogyria and lissencephaly. Muscle histology showed dystrophic features, rimmed vacuoles, and partial loss of laminin á immunoreactivity. Nerve conduction study was normal in both patients. High-throughput analyses using "NMD-Chips" DNA capture and next generation sequencing identified novel nonsense mutations of <i>LAMA2</i> gene at homozygous stage in the two patients. Previous sequencing of <i>LMNA, EMD, DES, FHL1, MYH7, FKRP, FKTN, COL6A1,2,3, SEPN1</i> genes disclosed no mutation. In summary, these 2 patients disclosed a mild limb-girdle-type pattern of weakness and contractures associated respectively in each patient with dilated cardiomyopathy and cortical dysplasia. Work partly supported by the NMD-CHIP Consortium, an European Commission FP7 HEALTH project (HEALTH-F5-2008-223026).

Does the Presence of Dystrophic Features in Patients With Type 1 Neurofibromatosis and Spinal Deformities Increase the Risk of Surgery?

Retrospective chart and radiographical review. To present the demographics of patients with scoliosis and neurofibromatosis type 1 (NF-1), to record the incidence of dystrophic features, and to determine whether the presence of dystrophic features increase the risk of surgery in patients with NF-1 and associated spinal pathology. The most common of the osseous complications of NF-1 is spinal deformity, occurring in 10% to 30% of individuals with NF-1. Many of these patients will eventually require surgery for curve progression, which makes study of demographics and identification of features predicting the need for surgery essential in this patient population. A retrospective review was performed in patients with NF-1 and spinal deformities, followed in a multidisciplinary neurofibromatosis center. A subset of 56 patients with complete radiographical evaluation was reviewed for identification of risk factors for spine surgery. One hundred thirty-one patients from a population of 694 patients with NF-1 (19%) had scoliosis. Mean age at diagnosis of scoliosis was 9 years (range; 1-17 yr). Scoliosis and need for surgery were equally distributed between males and females. In the group of 56 patients, 63% had 3 or more dystrophic features. The presence of 3 or more dystrophic features was the strongest predictor of the need for surgery (odds ratio = 14.34; P < 0.001). Individual features most predictive of need for surgery were the presence of vertebral scalloping (odds ratio = 13.19; P < 0.001) followed by the presence of dural ectasia (odds ratio = 6.38; P = 0.005). Patients with no dystrophic features were unlikely to progress to need for surgery. Scoliosis and need for surgery were equally distributed between males and females. The presence of 3 or more dystrophic features was highly predictive of the need for surgery, with the most significant individual predictors being vertebral scalloping and dural ectasia. A combination of radiographical and MRI features can be used to predict need for spinal surgery. 3.

Muscular dystrophy with large mitochondria associated with mutations in the CHKB gene in three British patients: Extending the clinical and pathological phenotype

Three patients with CHKB deficient muscular dystrophy are described which broadens the previously described phenotype. Blood smear in one patient showed Jordans anomaly (vacuolated leukocytes). Gastrointestinal features occurred in two patients and there appeared to be acute deterioration with infection/general anaesthesia. Brain imaging showed no structural changes but brain magnetic resonance proton spectroscopy (MRS) demonstrated significant reduction in choline:N-acetyl aspartate and choline:creatine ratios in keeping with a general decrease in the amount of choline and phosphocholine-based substrate. Muscle pathology showed either myopathic or dystrophic features, uneven oxidative enzyme staining, COX deficient fibres and peripherally located large mitochondria. CHKB activity was reduced in all three patients and complex 1 activity was significantly reduced in one patient.